Commercial processing of photographic film has become a well established industry. Commercial photographers produce large numbers of photographic exposures, and correspondingly large numbers of photographic negatives, even though the actual sale of photographs may constitute photographic prints of ten percent or less of the actual number of photographic exposures taken by the photographer. To avoid the expense incumbent in printing many exposures which will not ultimately be sold to the customer, the commercial photographic processing industry routinely deals with the developed negatives only as the method of evaluating the quality of the photographs. Sample prints or "contact sheets" are often produced for the commercial photographer's editing purposes.
In any photographic operation, it is important to maintain the developed negative in the event that reprints or edited reprints of a photograph are necessary. Photographic negatives, while necessary for these purposes, and useful in a variety of ways in the commercial photographic environment, are difficult to store and handle. Because they are relatively soft, they are subject to damage through mishandling. Because they are a negative image, they are difficult to correlate with real-life images. Finally, because they are small, lightweight and of low mass, they are easy to misplace, difficult to store, and difficult to manipulate in an automated environment.
Commercial photographic studios require accurate separation of photographic negatives from large rolls of developed film, transfer of photographic negatives to suitable storage media, and classification of the negatives in relation to the storage media to facilitate their storage and recovery. Photographic negatives also need to be protected from damage due to mishandling. Typically, these requirements have been met by storing the photographic negatives in separate envelopes designed specifically for that purpose. However, placement of individual photographic negatives in envelopes by hand is a tedious process, and subjects the photographic negatives to damage from mishandling. Accordingly, a number of methods have been employed for the automated cutting of photographic negatives from a long roll of such negatives, and for the placement of such negatives in storage envelopes.
Previous methods for separation and storage of photographic negatives include the use of a continuous supply of storage envelopes. The storage envelopes are presented to a device for cutting the negatives from a continuous roll and for automatically inserting the negatives into appropriate envelopes. Typically, the continuous supply of storage envelopes is configured for tractor feeding, with perforations allowing the individual envelopes to be separated from one another once the negatives have been cut and placed in the envelopes. This type of continuous supply of storage envelopes may be manufactured from a variety of materials, including paper, acetate, and paper-acetate combinations. The tractor feed strips are perforated for removal after use during insertion of the negatives.
Previous methods for accomplishing the abovedescribed task required a "leader" and "trailer" section on a continuous supply of storage envelopes. It was also necessary to thread the leader section through the entire portion of the mechanism of the negative bagger. This process results in a waste of a substantial number of storage envelopes.
Directing the cut negative into the envelopes has remained an imprecise procedure. Typically, the apparatus relied upon the force of gravity to direct a cut negative into an envelope located beneath the negative cutter. Because negatives have high surface area and low mass, they are easily affected by drafts and currents of air when allowed to drop freely; frequently causing the negatives to miss the opening in the envelope, and to become lost or damaged as a result. Occasionally, the negative would fill only partially into the envelope, requiring the operator to manually insert the negative further into the envelope to insure desired movement through the tractor feed mechanism.
To insure a clear opening in the envelope for the negative, existing machines use a blower located above the envelope. This blower directs air down toward the top of the envelope, thereby forcing it open. However, this method operates unreliably. The blower often blows both sides of the envelope in the same direction, thereby allowing the cut negative to fall outside the envelope. Other methods comprise mechanical arms with vacuum fittings which mechanically move to open the envelope. While this method is functional, the time required for the vacuum arm to lower into position, activate a vacuum source, raise to open the envelope, and deactivate the vacuum source involves substantial machine cycle time, significantly slowing the insertion operation. Further, the vacuum arm is very sensitive to variation in vacuum pressure. An excessive vacuum causes the bag to deform, inhibiting the entry of the negative; insufficient vacuum results in an ineffective grip on the envelope. Further, the vacuum is often sufficient to exert a vacuum through both layers of a coarse envelope material, causing both sides of the envelope to adhere to the vacuum.
The present invention is designed to overcome each of the above-referenced limitations, as will be seen in the detailed description of the drawings and invention which follow.